1 /* 2 * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 import java.io.File; 25 import java.io.FileDescriptor; 26 import java.io.FileNotFoundException; 27 import java.io.RandomAccessFile; 28 import java.lang.management.ManagementFactory; 29 import java.lang.management.OperatingSystemMXBean; 30 import java.lang.ref.Cleaner; 31 import java.lang.ref.Reference; 32 import java.lang.ref.ReferenceQueue; 33 import java.lang.ref.WeakReference; 34 import java.lang.reflect.Field; 35 import java.util.HashSet; 36 37 import com.sun.management.UnixOperatingSystemMXBean; 38 39 /** 40 * @test 41 * @bug 8080225 42 * @modules java.base/java.io:open 43 * @summary Test to ensure that an unclosed and unreferenced RandomAccessFile closes the fd 44 * @run main/othervm UnreferencedRAFClosesFd 45 */ 46 public class UnreferencedRAFClosesFd { 47 48 static final String FILE_NAME = "empty.txt"; 49 50 /* standalone interface */ 51 public static void main(String argv[]) throws Exception { 52 53 File inFile= new File(System.getProperty("test.dir", "."), FILE_NAME); 54 inFile.createNewFile(); 55 inFile.deleteOnExit(); 56 57 long fdCount0 = getFdCount(); 58 System.out.printf("initial count of open file descriptors: %d%n", fdCount0); 59 60 String name = inFile.getPath(); 61 RandomAccessFile raf; 62 try { 63 // raf is explicitly *not* closed to allow cleaner to work 64 raf = new RandomAccessFile(name, "rw"); 65 } catch (FileNotFoundException e) { 66 System.out.println("Unexpected exception " + e); 67 throw(e); 68 } 69 FileDescriptor fd = raf.getFD(); 70 71 Field fdField = FileDescriptor.class.getDeclaredField("cleanup"); 72 fdField.setAccessible(true); 73 Cleaner.Cleanable cleanup = (Cleaner.Cleanable)fdField.get(fd); 74 75 // Prepare to wait for FOS, FD, Cleanup to be reclaimed 76 ReferenceQueue<Object> queue = new ReferenceQueue<>(); 77 HashSet<Reference<?>> pending = new HashSet<>(3); 78 pending.add(new WeakReference<>(cleanup, queue)); 79 pending.add(new WeakReference<>(raf, queue)); 80 pending.add(new WeakReference<>(fd, queue)); 81 82 Reference<?> r; 83 while (((r = queue.remove(10L)) != null) 84 || !pending.isEmpty()) { 85 System.out.printf("r: %s, pending: %d%n", r, pending.size()); 86 if (r != null) { 87 pending.remove(r); 88 } else { 89 cleanup = null; 90 raf = null; 91 fd = null; 92 System.gc(); // attempt to reclaim the RAF, cleanup, and fd 93 } 94 } 95 96 // Keep these variables in scope as gc roots 97 Reference.reachabilityFence(cleanup); 98 Reference.reachabilityFence(fd); 99 Reference.reachabilityFence(raf); 100 Reference.reachabilityFence(pending); 101 102 // Check the final count of open file descriptors 103 long fdCount = getFdCount(); 104 System.out.printf("final count of open file descriptors: %d%n", fdCount); 105 if (fdCount != fdCount0) { 106 throw new AssertionError("raw fd count wrong: expected: " + fdCount0 107 + ", actual: " + fdCount); 108 } 109 } 110 111 112 // Get the count of open file descriptors, or -1 if not available 113 private static long getFdCount() { 114 OperatingSystemMXBean mxBean = ManagementFactory.getOperatingSystemMXBean(); 115 return (mxBean instanceof UnixOperatingSystemMXBean) 116 ? ((UnixOperatingSystemMXBean) mxBean).getOpenFileDescriptorCount() 117 : -1L; 118 } 119 }